Explosive composition for detonating rivets



Patented Dec. 3, 1940 EXPLOSIVE COMPOSITION FOR DETONATING RIVETS Phokion Naofim, Leverkusen-Schlebusch, Germany, assignor, by mesne assignments, to E. I. du Pont ale Nemours & 00., Wilmington, Del.

No Drawing. Application June. 28, 1939, Serial No. 281,737. In Germany July 14, 1938 2 Claims.

Riveting methods have already frequently been proposed in which the formation of the securing head is effected by detonation or explosion by means of explosive charge introduced into an interior chamber in the rivet shank. -More particularly as regards the deposition of the explosive mass and the ignition thereof, many ways and possibilities have been explored in this connection. The result of these have proved the difficulties involved in carrying out the proposals and severely limited these possibilities.

, Since in the case of rivets we are dealing usually with very small, or somewhat smallarticles, the explosive charge which is to efiect the necessary deformation can of course be only small. On the other hand; however, it is necessary that the explosive in question detonates with sulficient velocity in order to permit the deformation necessary for forming a tightly sitting looking head to take place, since a certain shattering is necessary herefor which amongst other things is conditioned also by the rate of interaction of the explosive. However, the velocity with which r particularly small quantities of explosive become converted is dependent to a great extent on the natureof the ignition. A high rate of conversion can be imparted to small quantities of not particularly sensitive explosives by means of a suitable initial ignition, whilst if the explosion of the explosive substance in question is to be brought about simply by sudden heating, either correspondingly large quantities of explosives must be employed or the explosives used must r according to its category be particularly sensitive and must approximatein its properties to the so-called initial explosives, which detonate even in minimum quantities with great violence in contact with a flame or with a hot object and with a detonation velocity approximating more or less to the theoretically possible maximum.

In addition there is the effect of an enclosure or a tamping of the small quantity of explosive which can be employed. It is known that such a tamping or a rigid enclosure raises the explosive action and will be of great influence on the velocity of conversion and the explosion pressure which develops just in the case of'the small quantities of explosive which here come into question.

In many cases it has proved to be desirable,

bearing in mind the metal material of the rivets,

' toav'oid. a tamping since the tamping material being ejected during the explosion may scratch or tear the metal, which may give rise to subsequent corrosion thereof. Consequently only those explosives have been found to be suitable which are sufficiently sensitive to undergo conversion with sufiicient velocity without tamping. In addition there is the fact that the use of a special initial ignition complicates the method in an impossible manner, so that only those explosives appear to be suitable which detonate with sufficient shattering power even in small quantities by'flame ignition or sudden heating to their ignition point. i

If the ignition is to be effected by rapid heating of the rivet, which appears to be convenient and advantageous in many respects, the further requirement must be imposed upon the explosive to be used for charging the rivet that it detonates at the lowest possibletemperature, but in any case at a temperature whichcan exert no unfavourable influence on the metal of naturally aged rivets and so removes the necessity of having to heat the rivets to too high a temperature.

An explosive which conforms to all these requirements has been found in hexamethylenetriperoxide-diamine, the interaction product of hydrogen peroxide on hexamethylene-tetramine. This substance detonates on heating to C. and with sufflcient shattering power even in small quantities and without tamping, which shattering power can be reduced in intensity as desired or required by addition of inert substances.

What I claim is:

1. An explosion rivet containing an explosive composition adapted to-expand the same comprising hexamethylene-triperoxide-diamine.

2. An explosion rivet containing an explosive composition adapted to expand the same comprising hexamethylene-triperoxide-diamine disposed in a cavity in the shank of said rivet.

PHOKION NAofiM, 

